1. Field of the Invention
The present invention relates to an automatic original conveying apparatus for use in an image forming apparatus such as a copying machine or a laser beam printer, and more particularly to an automatic recycling original conveying apparatus for recycling the original documents between an original stacker and an exposure position of the image forming apparatus.
2. Related Background Art
Conventional automatic recycling original conveying apparatus are generally so constructed as to feed the original documents stacked on an original stacker one by one from the lowermost one to the exposure position of an image forming apparatus such as a copying machine, and, after the exposure, return said original documents onto said original stacker, and repeat the above-explained operation by a number of cycles corresponding to the desired number of copies, wherein a cycle means the feeding operations of a number corresponding to the number of original documents in the stack.
In such automatic recycling original conveying apparatus in which the original documents stacked on the original stacker are separated in succession from the lowermost one, the separating condition varies significantly by the number of stacked original documents, and the separation becomes more difficult as the number of stacked original documents becomes larger. Consequently for achieving secure separation there is an upper limit of the number of stacked originals, and defective separation may occur if said upper limit is exceeded.
Also the original documents returned to the stacker need to be precisely aligned in order to be fed again. For this reason the original documents have to be securely aligned in the direction of width, and the documents may show positional error in the direction of width or may proceed in skewed position unless the operator sets a lateral defining plate in an appropriate position corresponding to the size of the original documents.
Also the two-folded or Z-folded originals have to be unfolded by the operator before setting on the stacker since such originals cannot be aligned satisfactorily when they are returned to the original stacker, but such originals may cause defective refeeding if they are not properly unfolded by the operator.